Many telecommunication systems have a number of access networks coupled to a local exchange. Each access network usually includes a digital line carrier coupled to the local exchange by a plurality of high-speed digital lines, e.g., a T1 or an E1 line. Typically, an interface, such as a V5.2 interface, defines the switching and signaling protocol between the digital line carrier and the local exchange. The access network provides for the connection of a number of transceivers, e.g., telephones, to the public switched telephone network (PTSN).
Typically, when using one of these systems to place a telephone call, for example, between a first transceiver and a second transceiver, the first transceiver is taken off hook, and the number of the second transceiver is entered into the first transceiver. The number is transmitted to the local exchange via a digital line carrier of an access network. Subsequently, the local exchange initiates a call establishment process, e.g., a V5.2 call establishment process, to complete the call to the second transceiver. In a typical case, each transceiver is associated with a different digital line carrier and access network. Further, the call establishment process includes allocating a time slot to each of the first and second transceivers in the high-speed digital links between the digital line carrier and the local exchange. However, in some cases, both transceivers are associated with the same digital line carrier.
One problem with the above setup is that when the first and second transceivers belong to the same access network and are coupled to the same digital line carrier, the first and second transceivers connect through the local exchange. This increases the load on the digital high-speed lines between the digital line carrier and the local exchange and thus increases the required number of lines.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for access networks that more effectively use available bandwidth in high-speed digital links between the local exchange and the digital line carrier.